Chair iron



Feb. 8,v 1944. H W, SHELDRICK v 2,341,124

' CHAIR IRON Fii'ed May 22, 1942 s sheets-sheet `1 Feb. 8, 1944.

H\ W. SHELDRICK CHAIR IRON Filed May 22, 19,42 3 Sheets-Sheet' 2 Feb. s, 1944.

H. W. SHELDRICK CHAIR IRON Filed May 22, 1942 3 Sheets-Sheet 3 aff' 5J fa WMM'M?.

Patented Feb. 8, 1944 Henry W. Sheldrick,

Collier-Keyworth Gardner, Mass., assgnor to Company,v

Gardner, Mass., a

corporation oi.` Massachusetts Application May 22, 1942, Serial No. 444,010 11` Claims. ('Cl. 155-77) construction and will be apparent from the con- A .sideration of the following description and by the accompanying drawings, wherein Fig. lis aside elevation of an oice chair embodying the vpresent invention;

Fig. 2 is `a top plan view, with parts broken away, of the chair iron;

Fig. 3 is a section on the line 3-3 of Fig. 2;

Fig. 4 is a view showing the relative positions of the seat, back and associated members of the chair iron at different angular positions; and

Figs. 5 and 6 are enlarged sections on the lines 5 5 and 6 6, respectively, of Fig. 3.

In accordance with the present invention I provide a chair comprising a base member which may be of any conventional design and construction, separate seat and back 'members which may also be of conventional design and construction, and a chair 'iron or support-ing mechanism carried by the base member `and supporting both the seat 'and back for tipping movement which may be readily controlled by adjusting certain parts of the chair iron, thereby securing, within the 'desired angular relationship between 'the seat and back which is most conducive to the comfort of the occupant.

The chair iron or supporting mechanism comprises a plurality of interconnected members constructed and arranged so as to provide, in eiect, 'a four-bar linkage wherein one oi the links is rigidly nxed `to the base, another link normally supporting the seat in a substantially horizontal position, a third link supporting the back in an upright position, and the fourth link being pivotally connected with the backsupporting link `and the fixed or stationary link and being manually vadjustalri'le so that the relative movements of the seat and back-supporting links may be varied. In addition I also provide means for yieldingly opposing tipping movement of the seat and back, which means not only is eiective normally to maintain the seat and ,back in substantially horizontal vand vertical positions, respectively, but also is capable of adjustment so that the force re- 55 quired to eiect tipping movement of the seat and back may be varied.

In the embodiment herein shown for the purpose of illustration, a conventional base or pedestal I is supported on casters 2, and a chair iron 3, carried by the "base, supports separate seat and back members 4 and 5. The seat and back members may be of conventional `design and construction and, if desired, the seat 4 may be provided with arm `rests 6, it being understood that the back rest` 5 is supported independently of the seat 4 and arm-6, as hereinafter described.

The chair iron 3 comprises a fixed member I0 having upstandng side walls II and I2, and is swivelly4 mounted on a pivotl I3 projecting upwardly from the cap 8 of the pedestal, the Xed member I being inclined as shown in Figs- 1 and 3. The upper forward end of the xed member `II) carries a laterally projecting pivot pin I4 on which the seat-supporting member I5 is pivotally mounted. The seat-supporting member I5 comprises a pair of spaced, parallel angle irons rigidly secured at the front and rear ends by -crossbars I7 and I8, the seat-supporting member bein-g mounted on the .pivot I4 approximately midway between thevcenter and front end of the seat, as shown more clearly in Fig. 1. The seat 4 is attached to the angle irons I6 and/orcrossbars I'I and IB-in any suitable manner, and the seat and arm rests are thus supported for tippingv movement about the pivot pin I4.

Therear end `of the seat-supporting member is pivotally connected by a pin 20 to the upper end of a vertically depending back-supporting member 2| of substantially U-shape cross-sec tion, which provides side walls 22 andr 23 having aligned openings for the reception of the ends of pivot 20. The back rest 5 is-secured to the outer face of the member 2| in any suitable manner, here shown as comprising a mechanism 24, operated by hand wheel-25, for adjustably positioning the back 5 vertically with respect to the seat 4. `Since such mechanism is well known'toA those skilled in the art, a description thereof is unnecessary.

AThe lower ends of the sidewalls 22 and 23 are pivotally secured by studs or rivets 26 and 2'I to one end of an adjustable member 3U (Figs. 3 and 5) which comprises an open-end, box-like coupling 3| having side walls 32 and 33 which receive the rivets 26 and 21, respectively, and a rear wall 34 formed with a central opening 35. A screw vshaft 36 has its reduced end rotatably mounted `,in the opening 35 and the lshaft is held against compression spring 62.

ing actuating shaft 52, the outer end of which.

carries an actuating member or hand wheel 54" conveniently located for manual operation by thev occupant, as shown in Fig. v1. The actuating shaft 52 is rotatably supported' in an opening 56 formed in the wall 32 andan opening formed in an upstanding bracket 51 welded or otherwise secured to the wall 3|. Rotation of the hand wheel 54 in one direction or the other effects rotation of the screw shaft 36 and hence increases or decreases the effective length of the adjustable member 30, thus varying the angular position of the back 5 relative to the seat 4.

yWith this construction and arrangement the members I5 and 2I, and the adjustable member 60, being pivotally interconnected as above described, constitute in effect a four-bar linkage,

illustrated in Fig. 4, wherein the xed member, the seat and back-supporting members, and the adjustable member are represented by the lines ab, ac, cd and db, respectively; the pivotal connections I4, 45, and 21 are respectively represented by the points a, b, c and d; the line ec represents the back 5; the lines ac', c'd' and db `representing the position of the three movable members when the seat and back are tilted to *their full extent; and the line fc' representing the vsame angular position of the back 5 relative to the seat (ca) as the normal angular position shown by the line ec.

Itwill be observed that when the seat and back are tilted from the normal position, shown by the lines ac and cd, to fully tilted position, shown vby the lines ac and c'd, the angular movement 'of theseat is represented by the angle cac'; the

movement of the back relative to the seat is represented by the angle fce' which equals the angle eca minus the angle eca; and the total movement of the back equals the angle fc'e' plus the angle cac'; In other words, the angle fce' represents the increased angular movement of fthe back over that of the seat. -bd (representing the adjustable member may 'be varied, the angular position of the back, repi resented by the angle ace, may be adjusted to -suit the comfort of the occupant without affect- Since the line ing the foregoing relationships.

In order yieldingly to restrain tilting move- "ment of the seat and back and effect the return 'of these parts from fully tilted to normal posi- 1tion, any suitable resilient means acting on the xed member and any of the movable members 'may be employed. As here shown (Figs. 3 and 6), the lower wall of the fixed member I0 is formed with an opening`66 surrounded by a boss or hub 6I to provide a seat for one end of a coil A depending extension member 64, rigidly secured to the angle iron I6 'of the seat-supporting member I5, has its lower end portion normally disposed in close proximity to the lower wall of the fixed member I0, asshown in Fig. 3, and an opening 65 formed in-theextension member 64 aligns with the opening'60, as shown in Fig. 6. A-bolt or screw shaft xed member I0, the seat and rback-supporting ISI) 66 extends axially through the spring 62 and the openings and 65, and its headed end carries a washer 61 against which the other end of the spring 62 acts, the threaded end of the bolt projecting outwardly beyond the extension member 64. A washer-like locking plate 10, formed with diametrically disposed recessed portions of grooves 1I, is welded or otherwise secured to the outer faceofthe extension and a U-shaped member or yoke 12 is carried by the bolt 66 with its tapered legs 14 extending into the recesses, as

shown in Figs. 1, 3 and 6. A washer 16 is interposed between the outer end of the yoke 12 and the hub 11 of a hand wheel 18 carried by the threaded end of the bolt. By rotating the hand wheel 18 in a clockwise direction, the spring 62 may be compressed, thus urging the extension and fixed members together and consequently yieldingly opposing tilting movement of the seat and back with a force dependent upon the degree of compression of the spring 62. The tapered legs 14 of the yoke 12 provide a pivot point or knife edge on which the spring bolt assembly is free to rock as the angle between the center line of the bolt and the front face of the extension 64 changes as the seat is tilted.

With this construction and arrangement the hand wheel 18 may be rotated in one direction or another to vary the action of the spring 62, thus permitting the seat and back to be tilted Aunder conditions controllable by the occupant to suit his comfort. It will be observed that the hand wheel 18, being located beneath the seat 4, is readily accessible for convenient manipulation and that when the proper adjustment of the spring 62 has been made, the hand wheel 18 is frictionally locked against accidental rotation. It will also be observed that the hand wheels 25 and 54 are likewise located for convenient manipulation by the occupant and hence the height and angular position of the back 5, as well as the tilting action permitted by the spring 62, may be readily controlled by a person occupying the seat.

It will be noted that in'a chair constructed in accordance with the present invention the front edge of the seat does not rise appreciably when the chair is tilted from normal horizontal position, because the pivot pin I4 is located near the front, and hence occupants of varying weight may sit comfortably in the chair without changing the adjustment of the spring 62, since rearward pressure must be exerted on the back 5 before the seat will tilt downwardly. The tilting action of the seat 4 and the rearward movement of the back 5 are dependent on both the spring 62 and the leverage of the back 5 and supporting member 2| about the pivotal connection 20; and in the normal use of the chair the extent of this movement is controlled by the rearward pressure exerted by the shoulders of the occupant, rather than by the weight of the occupant on the seat. This desirable feature is possible only when and because the angular travel lof the back exceeds that of the seat, as indicated in Fig. 4, wherein the angle between ed and ed exceeds the angle cac by angle fce'.

While I have shown and described one desirable embodiment of the invention, it is to be understood that this disclosure is for the purpose of illustration and that various changes in shape, proportion and arrangement of parts, as well as the substitution of equivalent elements for those herein shown and described, may be made without departing from the spirit andscope -ot the invention as set forthlin the appended claims.

I claim:

l.. In a chair of the type having separate seat and back members, a chair iron for supporting the seat and back members for simultaneous tipping movement, comprising a xed member, a seat-supporting member pivotally connected to said fixed member, a back-supporting member pivotally connected to said seat-supporting member, and an adjustable member pivotally connected to said Xed member at a point spaced from the pivotal connection with said seat-supporting member and to said back-supporting member at a point spaced from the pivotal `connection with said seat-supporting member, said xed member, seat-supporting'member, backsupporting member, adjustable member and their respective pivotal connections providing a `fourbar linkage system in which said adjustable member controls a relative tipping movement of the seat and back members.

2. In a chair of the type having separate seat and back members, a chair iron for supporting the seat and back members for simultaneous tipping movement, comprising a xed member, a seat-supporting member pivotally connected to said fixed member, a back-supporting member pivotally connected to said seat-supporting member, an adjustable member pivotally connected to said iixed member at a point spaced from the pivotal connection with said seat-supporting member and to said back supporting member at a point spaced from the pivotal connection With said seat-supporting member, said fixed member,

seat-supporting member, back-supporting member, adjustable member and their respective pivotal connections providing a four-bar linkage system in which said adjustable member controls a relative tipping movement of theseat and back members, and means associated with the fixed member and seat-supporting member for yieldingly opposing tipping movement of the seat and back members.

'3. In a chair of the type having separate seat and back members, a chair iron for supporting the seat and back members for simultaneous tipping movement, comprising a iixed member, a substantially horizontally disposed seat-supporting member pivotally connected adjacent to its front end to said fixed member, a substantially vertically disposed back-supporting member pivotally connected at its upper end to the rear of said seat-supporting member, and an adjustable member pivotally connected at one end to said fixed member at a point spaced from the pivotal connection with said seat-supporting member and at its opposite end to the lower part of said back-supporting member, said fixed member, seatsupporting member, back-supporting member, adjustable member and their respective `pivotal connections providing a four-bar linkage system in which said adjustable member controls a relative tipping movement of the seat and back members.

4. In a chair of the type having separate seat and back members, a chair iron for supporting the seat and back members for simultaneous tipping movement, comprising a fixed member, a substantially horizontally disposed seat-supporting member pivotally connected adjacent to its front end to said xed member, a substantially vertically disposed back-supporting member pivotally connected at its upper end to the rear of said seat-supporting member, an adjustable ysaid screw shaft, said iixed front end to vvertically disposed back-supporting member piv- `otally connected at its upper end to the rear of said seat-supporting member, and an adjustable -Y member pivotally connected at one .end to said Aixed member at a point spaced from the .pivotal connection with said seat-supporting member and at its opposite end to the lower part of said back-supporting member, said fixed member, seat-supporting member, back-supporting member, adjustable member and their respective pivotal connections providing a four-bar linkage system in which said adjustable member controls a relative tipping movement of the seat and back members, and spring meansacting on said fixed member and seat-supporting member for yieldingly opposing tipping movement of the seat and back members.

5. In a chair of the type having separate seat and back members, a chair iron for supporting the seat and back members for simultaneous tipping movement, comprising a fixed member, a seat-supporting member pivotally connected to said xed member, a back-supporting member pivotally connected to said seat-supporting member, and an adjustable member comprising a. coupling pivotally connected tosaid back-sup.- porting member, a screw shaft having one end rotatably mounted in said coupling, a second coupling connected to said xed member, said second coupling having a threaded socket receiving member, seat-supporting member, back-supporting member, adjustable member and their respective pivotal connections providing a four-bar linkage system in which said adjustable member controls a relative tipping movement of the seatand back members, and means for rotating said screw shaft so as to vary the effective length of the adjustable member. f

6. In a chair of the type having separate seat and back members, a chair iron for .supporting -the seat and back members for simultaneous tipping movement, comprising a xed member, a substantially horizontally disposed seat-supporting member pivotaliy connected adjacent to its said xed member, a substantially member comprising a coupling pivotally connected to said back-supporting member, a screw shaft having one end rotatably mounted in said coupling, a second coupling connected to said xed member, said second coupling having a threaded socket receiving said screw shaft, said fixed member, seat-supporting member, backsupporting member, adjustable member and their respective pivotal connections providing a fourbar linkage system in which said adjustable member controls a relative tipping movement of the seat and back members, and means for rotating said screw shaft so as to vary the eiTective length of the adjustable member.

7. In a chair of the type having separate seat and back members, a chair iron for supporting the seat and back members for simultaneous tipping movement, comprising a fixed member, a seat-supporting member pivotally con.- nected to said fixed member, a back-supporting member pivotally connected to said seat-supporting member, and an adjustable member comprising a coupling pivotally connected to said back-supporting member, a screw shaft having one end rotatably mounted in said coupling, a second coupling connected to said xed member, said second coupling having a threaded socket receiving said screw shaft, an actuating member carried by one of the coupling members, said 4 vfixed member, seat-supporting member, back- 'supporting member,

vping movement of the adjustable member and their respective pivotal connections providing a four-bar linkage system in which said adjustable member controls a relative tipping movement of the seat and back members, and means operatively associated with said actuating member and screw shaft for effecting rotation of the latter in response to actuation of the former, thereby to vary the effective length of the adjustable member.

8. In a chair of the type having separate seat and back members, a chair iron for supporting the seat and back members for simultaneous tipping movement, comprising pivotally connected seat and back-supporting members, a xed member pivotally connected to the seat-supporting member, and an adjustable member pivotally connected to the xed member and back-supporting member, said fixed member, adjustable member and seat and back-supporting members being arranged to provide a four-bar linkage system wherein said adjustable member controls the tipping movement of the back relative to the seat.

9. In a chair of the type having separate seat and back members, a chair iron for supporting the seat and back members for simultaneous tipping movement, comprising pivotally connected seat and back-supporting members, a xed member pivotally connected to the seat-supporting member, an adjustable member pivotally connected to the fixed member and back-supporting member, said xed member, adjustable member and seat and back-supporting members being arranged to provide a four-bar linkage system wherein said adjustable member controls the tipback relative to the seat, an extension member depending from the seatsupporting member with its in close proximity to said xed member, and resilient means acting on said xed member and the extension member for yieldingly opposing tipping movement of the seat and back members.

10. In a chair of the type having a seat supported to tip from a substantially horizontal poend portion disposed "sition to an inclined vmember carried by said sion member depending from said position, a chair iron having a xed member, a seat-supporting member pivotally connected to said fixed member, an extension member depending from said seat-supporting member, resilient means acting on the fixed and extension members so as to oppose tilting movement of the seat, and adjustable means for varying the action of said spring on thev extension and fixed members, said adjustable means including a screw projecting through aligned openings in the xed and extension members, the marginal portions about the opening in one of said members being provided with diagrammatically disposed recessed portions, a U-shaped screw shaft with its legs extending into said recessed portions, and an operating member having a threaded engagement about said screw shaft and acting on said U- shaped member so that the latter exerts a frictional locking action tending to oppose relative rotation of the screw shaft and actuating member.

11. In a chair of the type having a seat supported to tip from a substantially horizontal position to an inclined position, a chair iron having a iixed member, a seat-supporting member pivotally connected to said iixed member, an extenseat-supporting member, a spring having one end acting on the xed member, a screw shaft projecting through aligned openings in the extension and fixed members, means carried by the screw shaft for acting on the opposite end of said spring, a locking plate disposed about the opening in the extension member, said locking plate being formed with diagrammatically disposed recessed portions, a U.-shaped member carried by the screw shaft with its legs extending into said recessed portions, and an operating member having a threaded engagement about said screw shaft and acting on said U-shaped member so that the latter exerts a frictional locking action opposing relative rotation of the screw shaft and actuating member.

HENRY W. SHELDRICK. 

